If you've ever wondered how Allison's skin is so flawless, she takes extra special care of it. And thanks to being named the spokesmodel of the uber-gentle skincare line Simple, she can now do just that.

We, too, were curious about how she keeps her complexion looking crystal clear, so we called up the gorgeous Girls actress to find out a little more about her beauty routine.

Cosmo: Were you familiar with Simple's products before they contacted you to be the face of the brand?

Allison Williams: I had been introduced to the line by a friend of mine in the UK. My gateway product was the cleansing wipes. I would have her send them to me in the US, which was probably illegal but I had to have them.

AW: I've tried a bunch of their other products and love the entire line. But I have to work carefully with my skin, since it's really sensitive. So I don't use anything harsh on it, and Simple's products don't make my skin angry.

I'm always carrying the exfoliating wipes and the eye makeup remover wipes though. On a flight or after I'm wearing full makeup, I use them to clean my face. And I use the wipes right on the plane—I don't care who's in the seat next to me. As soon as the plane lands, I'm using them.

Cosmo: Can you walk us through your skincare regimen on a typical day?

[Then,] at the end of the day I use the exfoliating wipes and eye makeup wipes, followed by the hydrating light moisturizer. I love that one because a pet peeve of mine is feeling like your cream is coming off on your pillow, and this doesn't feel like it's packed on yet sliding off.

Cosmo: What is your can't-leave-home-without beauty product?

AW: The original Chapstick is my main hang. I stock up on them like they're going out of style, which I know they aren't. I also really love this French product called Homeoplasmine, which I have to get my fancy French-living friends to get for me. It's an amazing ointment that can be used for anything.

Cosmo: Now let's talk fashion. Your character Marnie on Girls is pretty polished. Do you relate to her look in your personal life?

AW: I think I have the capacity to be polished, but I'm more of a jeans person on a regular day. But Marnie always tries to look perfect all of the time. My wish for her is that she'd realize that she doesn't always have to care what people think.

When I want to be presentable, I like to be put together; otherwise I don't think about what I look like. On the red carpet [though], I focus on wearing things that I can breath in and shoes that I can walk in. I think my main objective is to wear things that I'll look back on fondly. The worst possible scenario is that it's boring but I tell my stylist that's fine with me, because I'd rather have that instead of not expressing myself.

Cosmo: Who is your style icon?

AW: I look at Grace Kelly as my inspiration and I try to emulate her as best as I can.

For more of Allison Williams, watch Girls Sundays at 9pm EST on HBO and to learn more about Simple, click here.